Study On Typing Of Staphylococcus Aureus By Maldi-TOF MS Combined With Drug Resistance Spectrum And PFGE

Objective: In this study,we identify suspected Staphylococcus aureus strains.Through drug sensitivity test,the drug resistance status of Staphylococcus aureus in Gansu Provincial Hospital is understood.We type Staphylococcus aureus to determine the correlation between strains and the prevalence status of the strains by using three methods:drug resistance spectrum typing,PFGE typing and MALDI-TOF MS typing.We also compare the similarities and differences between their typing results and discuss the feasibility of using MALDI-TOF MS technology to type Staphylococcus aureus.Methods: Suspected Staphylococcus aureus strains were collected,which were isolated from April 2017 to October 2017 in a Grade 3A hospital of Gansu.Gram stain microscopy was used for preliminary screening of Staphylococcus aureus.MALDI-TOF MS technology was used for confirmation.K-B method was used for drug sensitivity test.Finally,drug resistance spectrum typing,PFGE typing and MALDI-TOF MS typing were used to type Staphylococcus aureus.Result: All 44 strains were identified as Staphylococcus aureus by Gram stain microscopy screening and MALDI-TOF MS technique confirming.Except vancomycin and linezolid,Staphylococcus aureus exhibited different degrees of resistance to other antimicrobial agents.All strains were resistant to penicillin.MRSA and MSSA accounted for 54.5%(24/44)and 45.5%(20/44)respectively.44 strains were typed into 17 types by drug resistance spectrum typing.39 strains of Staphylococcus aureus could be typed into 15 types by PFGE typing,but 5 strains couldn't be typed.All strains were typed into 17 types by MALDI-TOF MS typing.Conclusion:1.MALDI-TOF MS can identify Staphylococcus aureus quickly and accurately.2.Staphylococcus aureus exhibited different degrees of resistance to 13 antimicrobial agents.The number of MRSA is more than of MSSA.3.The drug resistance spectrum typing can successfully types Staphylococcus aureus.The required data are derived from the drug sensitivity test,which are easy to get.Its results are comparatively consistent with the PFGE typing results.4.PFGE typing can be used for typing Staphylococcus aureus,and its typing rate and resolution are high,but there are cases where the strain cannot be typed due to the absence of electrophoretic banding.5.MALDI-TOF MS technology has the potential to be used for bacterial typing.It can successfully type Staphylococcus aureus.It's easy and fast to operate,and has certain resolution.However,its results were quite different from the results of drug resistance classification and PFGE classification.So further research is needed.